As well as having a tailored functionality, modern plastics are also intended to do increased justice to environmental concerns. As well as by a general optimization of preparation processes, this can also be achieved through the use of greenhouse gases, such as carbon dioxide, as building blocks for the synthesis of polymers. Accordingly, for example, a better environmental balance for the process can be obtained overall via the fixing of carbon dioxide. This path is being followed in the area of the production of polyethercarbonates, and has been a topic of intense research for more than 40 years (e.g., Inoue et al, Copolymerization of Carbon Dioxide and Alkylenoxide with Organometallic Compounds; Die Makromolekulare Chemie 130, 210-220, 1969). In one possible preparation variant, polyethercarbonate polyols are obtained by a catalytic reaction of epoxides and carbon dioxide in the presence of H-functional starter substances (“starters”). A general reaction equation for this is given in scheme (I):

A further product, in this case an unwanted byproduct, arising alongside the polythercarbonate is a cyclic carbonate (for example, for R═CH3, propylene carbonate).
As shown above, polyethercarbonate polyols have OH-functionalities, and this makes it possible in principle for relatively high molecular mass crosslinking products to be produced in further reactions, as by the addition of diisocyanates or polyisocyanates, for example. It would, however, be desirable to establish still further possibilities for the functionalization of the polymer scaffold, such possibilities being amenable to utilization in reactions including subsequent crosslinking reactions. One possibility for this is afforded by the copolymerization of monomers containing unsaturated groups which are able subsequently to act as functional groups.
EP A 2604641 discloses a process for preparing polyetherestercarbonate polyols by catalytic addition of carbon dioxide, alkylene oxides and cyclic anhydrides onto H-functional starter substances in the presence of double metal cyanide (DMC) catalysts.
EP-A 2604642 discloses a process for preparing polyethercarbonate polyols by catalytic addition of carbon dioxide and alkylene oxides onto H-functional starter substances in the presence of DMC catalyst which has been activated in the presence of cyclic anhydride.
The publication J. Polym. Sci. Part A (2006) 44(18) 5329-5336 describes polycarbonates prepared from alkylene oxide, allyl glycidyl ether and CO2 using ternary rare-earth catalysts (glycerol and diethylzinc modified with Y salts). The epoxide-CO2 copolymerization produces virtually alternating polymers.
The publication Journal American Chemical Society (2004) 126 11404-11405 describes the alternating copolymerization of limonene oxide and CO2. Zinc β-diiminates are used as catalysts.
WO-A 2013/016331 discloses formulations for producing polyurethanes and also the polyurethanes produced accordingly (such as foams, TPUs, and elastomers) based on aliphatic polycarbonate polyols having an alternating carbonate-alkylene oxide structure.
WO-A 2010/028362 discloses the preparation of predominantly alternating polycarbonate polyols by reaction of epoxides with CO2 with catalysis by metal complexes, typically Co(III)-salen complexes, and optionally co-catalysts, in the presence of protic chain transfer agents, preferably diols, such as low molecular mass diols and hydroxy-functional polyesters and polyethers.
Polymer (2006) 47, 8453-8461 and, J. Polymer Research (2009) 16, 91-97, disclose the terpolymerization of alkylene oxides with maleic anhydride and CO2 in the presence of polymer-supported double metal catalysts or supported zinc glutarate catalysts. Characteristics described include the increase in the glass transition temperature through the incorporation of the anhydride, and the crosslinking with dicumyl peroxide at 170° C. over several minutes. The increased glass transition temperature and the associated increased viscosity hinder the processing of the resulting products. For many applications, the curing temperatures are too high and the curing times too long.
Journal of Polymer Science Part A: Polymer Chemistry (2006) 44 (18) 5329-5336 describes terpolymers of propylene oxide, allyl glycidyl ether, and CO2 which can be crosslinked by UV radiation. For many applications, however, this specific mode of curing is too slow.